To achieve real cost cuts, Delta must encourage more customers to purchase tickets online. To asssess the effectiveness of Delta's online operation, Baseline magazine asked Web monitoring service Empirix, of Waltham, Mass., to measure and rate the performance of eight airlines' reservation systems.

The test: Empirix automatically chose the "reservation" link on each home page, entered an origination airport (New York's LaGuardia) and a destination airport (Chicago's O'Hare), and recorded results. Each airline's system was tested hourly for two months.

The sites were tested for:

availability, with the best sites up and running the most times;

efficiency, where the best sites delivered information the fastest;

consistency, where the best result was the smallest swing in response times; and

accuracy, where the best scores are high scores, indicating the right information is delivered regularly.

PhocusWright, a travel research firm, helped weight the categories in terms of importance to customers. Empirix then calculated the final rankings, with the top total score becoming a 10.

Delta led the pack in availability and consistency, but ranked only fifth in accuracy. Southwest was best overall, earning the 10.